Clamp

ABSTRACT

An article clamp ( 10 ) of the band type including an elongated flexible band ( 11 ) having on one side a plurality of spaced teeth ( 20 ) and a head ( 14 ) having a chamber ( 22 ) for receiving screw ( 23 ) for cooperation with the teeth ( 20 ) on the band ( 11 ), a proximal end ( 12 ) of the band ( 11 ) being connected to the proximal end ( 15 ) only of the head ( 14 ) such that the distal end ( 16 ) of the head ( 14 ) is spaced from and free of the band ( 11 ), the head ( 14 ) further having a passage ( 30 ) therethrough for receiving a distal end ( 13 ) of the band ( 11 ) to form the band ( 11 ) into a loop.

TECHNICAL FIELD

This invention relates to a clamp and more particularly to clamp of thetype in which a band is looped around an article to be gripped such as ahose or pipe and tightened to clamp about the article.

BACKGROUND ART

A number of different designs and types of hose or pipe clamps arecurrently available. Generally, the known hose or pipe clamps include ametal strap which is fixed at one end to a separate metal housing, thehousing defining a recess which has its longitudinal axis aligned withthe axis of the strap. A worm screw is captured within the housingrecess and cooperates with an end of the strap which is looped about anarticle to be gripped. For this purpose, the strap is provided withspaced recesses or slots for cooperation with the threads on the wormscrew such that when the worm screw is rotated in opposite directionsthe metal strap loop is tightened to grip the article or loosened tofree the article. The housing is attached to the one end of the strap bya number of different arrangements. In one arrangement, the housing hasextended side flanges which are turned over on the underside of thestrap and which have opposite tongues which extend into slots in thestrap. Alternatively, the housing may be welded to the strap. Examplesof the above type of clamp strap are shown in DE 3121202 and U.S. Pat.No. 5,473,798. Whilst these clamps generally function efficiently, theyare not suited to being manufactured from plastics. Further, as a numberof steps are required in their construction such as joining of thehousing to the strap, the cost of manufacture of clamps of this type canbe high. A disadvantage of the above clamps is that the housing in useis held against the periphery of the article being gripped howeverbecause the housing is often of planar form on its side adjacent thearticle, it will not lie flush with a curved surface around which thestrap is looped. This can make tightening of the strap difficult andfurther when tightening occurs, the full circumference of the curvedsurface is not closely gripped because of the planar surface of thehousing is in contact with the curved surface of the article.

U.S. Pat. No. 4,047,268 discloses a moulded plastics worm gear clampingapparatus in which the housing for the worm screw is formed integrallywith a strap and extends a distance along the strap, the housing havinga curved surface to match the surface of an article to be clamped. Thestrap is looped about the article and passed into the worm screw housingto be engaged by the screw which when tightened reduces the size of thelooped strap to effect a clamping action about the article. As however,the housing forms part of the strap and is coextensive with the strap,tightening of the strap about the article will apply a radially inwardlydirected force tending to cause a radial distortion of the housingleading to possible screw slippage. This will limit the extent to whichthe strap can be tightened and therefore limit the applications to whichthe strap can be put. This disadvantage is further amplified if thecurved surface of the housing does not match a curved surface of thearticle being clamped. If the clamp is used with articles of smallerdiameter, incomplete clamping of the article about its periphery isachieved leading to potential leakage in pressure applications. Inarticles of a larger diameter, again an area adjacent the driving headwill not be evenly clamped. Thus a range of different clamps arerequired to suit the radius of each size article to be clamped. Furtherthe angled outer surface of the housing creates additional problems inthat radial distortion of the driving head will substantially increasethe risk of the screw slipping or substantially reduce the pressurewhich can be applied by the clamp. Similar disadvantages to thosereferred to above are associated with the clamps shown in GB 2326438, DE3400681 and U.S. Pat. No. 3,914,832.

International Publication No. WO 98/23889 discloses a metal strap clampin which the strap is attached to or extends from the front end of thescrew housing via a bearing or flange which is of greater thickness thanthe strap, the bearing or flange being curved to match the curve of anarticle to be clamped. The flange is formed integrally with the housingand rigid with the housing and the strap will bend about its join to therigid flange when tightened thus limiting the extent to which the clampcan be applied to smaller articles. Thus again many different sizeclamps with flanges of different radii will be required to suitdifferent size articles.

SUMMARY OF THE INVENTION

The present invention aims to provide a clamp of the type having a bandwhich can be looped and tightened about an article to be gripped orclamped and which may be applied to articles of a large range of sizes.The present invention in a further aspect aims to provide a clamp whichis constructed of a plastics material and which is therefore relativelyinexpensive. Other objects and advantages of the invention will becomeapparent from the following description.

The present invention thus provides an article clamp comprising:

-   -   an elongated flexible band, said band having on one side a        plurality of spaced teeth, said band having a proximal end and a        distal end,    -   a head having a chamber for receiving screw means for        cooperation with said teeth on said band, said chamber having a        longitudinal axis and said head having a proximal end and a        distal end, the proximal end of said band being connected to        said proximal end only of said head and extending away therefrom        at an acute angle to said head relative to said longitudinal        axis of said chamber such that said distal end of said head is        spaced from and free of said band,    -   said head flirter having a passage extending longitudinally        therethrough from said proximal end to said distal end for        receiving said distal end of said band to form said band into a        loop, and    -   said screw means being adapted in use to cooperate with said        teeth on said band such that when said screw means is rotated in        a first direction, said loop is decreased in size to clamp        around a said article.

The band may include a section extending from the proximal end of thehead which is of an arcuate configuration longitudinally of the band soas to enable it to more easily conform to the shape of a curved surfaceof an article being griped. The head may extend generally in atangential direction relative to the band section. The band section issuitably free of the teeth and thus is smooth on opposite sides. Theband has a main body carrying the teeth and suitably the main body is ofa substantially constant cross section up to its connection to the head.

The head of the clamp preferably includes a main body in which thechamber is located. A passage is suitably formed through the head toreceive the band, the passage extending substantially parallel to thelongitudinal axis of the chamber. The passage is suitably of re-entrantform in cross section such that the band can be captured therein. Thepassage is suitably intersected along its length by the chamber therebydefining an entrance into the chamber through which the teeth of theband can project for engagement by the screw means.

The passage is suitably defined between a planar rear wall and the mainbody of the head, the planar rear wall extending parallel to the chamberaxis. Preferably the connection between the band and the head is madebetween an end of the wall at the proximal end of the head and the band,the band thus extending at an acute angle away from the wall and in thedirection of the head. Preferably lateral extensions on opposite sidesof the band provide additional support to the band at its connection tothe wall and thus the head, the lateral extensions preferably beingintegral with the wall and band. Preferably, a flexible finger alignedwith the wall extends beyond the connection of the band to the wall, theflexible finger being sandwiched in use between the band and articleclamped adjacent the head.

Most preferably, the clamp is formed of plastics material by mouldingwith the head formed integrally with the band. The teeth suitablycomprise a plurality of raised lugs formed integrally with and extendingtransversely of the band. The teeth on the band are suitably in the formof transversely extending square threads. The threads may extendlinearly across the band or may follow a curved path. Preferably, theteeth terminate short of opposite side edges of the band.

Preferably the chamber of the head is substantially circular in crosssection so as to closely accommodate the screw means but permittingrotation thereof. Preferably the chamber is open at the distal end ofthe head to allow insertion of the screw means therein and is closed bya transverse wall at its proximal end for cooperation with an inner endof the screw means to resist forces applied by the screw means to theband.

Preferably, the screw means is in the form of a worm screw provided witha shank having a tread thereon for cooperation with the teeth of theband. The thread suitably comprises a square thread whose pitchcorresponds to the pitch of the teeth of the band. The worm screwsuitably includes a head provided with screw slot to enable rotationthereof in opposite directions with the aid of a screwdriver. The headof the worm screw additionally or alternatively may be shaped so as tobe adapted for cooperation with a spanner or socket tool. The head ofthe screw for this purpose may have a hexagonal configuration.

The worm screw may be formed integrally with the remainder of the clampduring manufacture and may be broken off to enable insertion in thechamber of the head for use.

In a further aspect, the present invention provides a moulded plasticsarticle clamp comprising:

-   -   an elongated flexible band, said band having a proximal end and        a distal end,    -   a head formed integrally with said band and having a chamber        therein, said chamber having a longitudinal axis and said head        having a proximal end and a distal end, the proximal end of said        band being connected to said proximal end of said head and said        band extending away from said head at an acute angle to said        head relative to said longitudinal axis such that said distal        end of said head is spaced from and free of said band,    -   said head further having a passage therethrough extending from        said proximal end to said distal end for receiving said distal        end of said band to form said band into a loop, and    -   a worm screw in said chamber for cooperating with said band        whereby rotation of said screw in a first direction about said        longitudinal axis causes said loop to be decreased in size to        clamp around a said article.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be more readily understood and put intopractical effect, reference will now be made to the accompanyingdrawings which illustrate a preferred embodiment of the invention andwherein:

FIG. 1 illustrates the clamp according to an embodiment of the inventionin side elevational view with the component parts separated;

FIG. 2 is a plan view of the band and head of the clamp;

FIG. 3 is a front view of the band and head of the clamp;

FIG. 4 is a perspective view of the band and head and associated wormscrew of the clamp;

FIG. 5 illustrates the clamp clamped about a first article; and

FIG. 6 illustrates the clamp clamped about an article of smallerdiameter than the article of FIG. 5.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to the drawings and firstly to FIGS. 1 to 4, there isillustrated a clamp 10 and components thereof according to an embodimentof the present invention. The clamp 10 may commonly be used as a hose orpipe clamp or for clamping cables or other like articles but it may beused to loop about and clamp any article or articles of any crosssection. The clamp 10 comprises an elongated flexible band 11 having aproximal end 12 and a distal end 13 and an integrally formed screwsupporting head 14 at the proximal end 12 of the band 11. The band 11may as indicated by the dotted outline FIG. 1 be of any length. The head14 has a proximal end 15 and a distal end 16 and as shown in FIG. 1, theproximal end 12 of the band 11 is only joined to the head 14 adjacentits distal end 15 at 17. The remainder of the head 14 is free of theband 11 such that the distal end 16 of head 14 is spaced from the band11.

The band 11 includes a generally strip-like main body 18 of flatrectangular cross section which is substantially constant along thelength of the band 11 and which includes a curved section 19 which issmooth on opposite sides and which includes the proximal end 12 of theband 11 which is connected to the head 14. The head 14 thus extendssomewhat tangentially to the section 19 from the proximal end 12 thereofand the band section 19 and plane containing the band section 19 extendsat an acute angle from the head 14 at an initial angle of about 30degrees. The body 18 of the band 11 apart from the section 19 isprovided on one side, normally the outer side, with a plurality ofregularly spaced lugs or teeth 20 which project from the one side of thebody 18. The teeth 20 extend transversely of and at an angle to thelongitudinal axis of the body 18. The reverse or inner side of the body18 is substantially smooth and uninterrupted. The teeth 20 are in theform of a square thread in cross section and extend linearly across thebody 18 of the band 11 but terminate short of opposite side edgesthereof. The teeth 20 however may be of a curved configurationtransversely of the body of the band 11.

The head 14 includes a main body 21 in which a chamber 22 of generallycylindrical configuration is provided, the chamber 22 extendinglongitudinally of the head 14 for receiving a worm screw 23. Thelongitudinal axis X-X of the chamber 22 thus also extends generallytangentially to the section 19 of the band 11. The side walls 24 of thebody 21 surrounding the chamber 22 are relatively thick to preventdistortion of the body 21 when stressed during tightening of the band11. The chamber 22 is open at 25 at the distal end 16 of the head 14 butis substantially closed at the proximal end 15 of the head 14 by atransverse end wall 26. The wall 26 is also relatively thick to opposeaxial forces applied by the screw 23. The body 21 in this embodiment isof stepped configuration with the lower portion 27 of the body 21stepped inwardly and therefore having thinner side walls than the walls24 of the upper portion where maximum forces are encountered.

The worm screw 23 has a shank 28 which carries an external thread 29 ofa square configuration for complementary cooperation and mating with theteeth 20 of the band 11, the pitch of the teeth 20 being the same as thepitch of the thread 29. The worm screw 23 further has a head 30 whichmay include a screw-driver slot 31 and/or may be configured to cooperatewith a suitable tool such as by being of hexagonal shape for cooperationwith a socket tool. The maximum external diameter of the worm screw 23including the threads 29 is slightly less than the internal diameter ofthe chamber 22 so that the worm screw 23 can be neatly received in thechamber 22 with a small clearance so as to permit rotation of the screw23 but restraining the screw 23 sufficiently to maintain engagement withthe teeth 20 of the band 11 in use.

A passage 32 is also formed in the head 14 to extend through the head 14from the proximal end 15 to the distal end 16 and parallel to thechamber 22, the passage 32 being defined between a rear planar wall 33,which extends parallel to the chamber axis X-X, and the main body 21 ofthe head 14, the wall 33 being joined to the main body through integralside flanges 34. The chamber 22 intersects the passage 32 along itslength on the inner side of the passage 32 to form an entrance region 35such that the passage 32 is of a re-entrant form to capture the band 11therein. The passage 32 in cross-section is similar to the cross sectionof the body 18 of the band 11 such that the band 11 may be neatlyreceived therein to enable its sliding movement through the passage 32with the teeth 20 extending through the region 35 into the chamber 22(as shown in dotted outline in FIG. 2).

The join 17 between the band 11 and head 14 is defined by an integraljoin between the lower end of the wall 33 and across the full width ofthe band 11. The band 11 is further supported on opposite sides bylateral extensions 36 formed integrally with the band 11 and wall 33,the extensions 36 providing additional support to the band 11 to reducethe possibility of fatigue cracking of the band 11. The wall 33 isextended on its lower side to define a finger 37 which is of the samewidth as the band 11 and effectively forms an extension of the band 11.The finger 37 projects beyond the connection 17 between the band 11 andthe head 14 and is tapered at its free end at 38.

In use and as shown in FIG. 5, and where the clamp 10 is required to beclamped around an article or group of articles 39 in this illustrationof circular cross section, the distal end 13 of the band 11 is insertedinto the rear end of the passage 32 through the head 14 to form a loop40 about the articles 39. In this position, the lugs or teeth 20 extendinto the chamber 22 to be adjacent to the screw 23 for cooperation withthe thread 29 on the shank 28 of the screw 23. Clockwise rotation of thescrew 23 will cause through cooperation between the screw thread 29 onthe shank 28 and the lugs or teeth 20, the band 11 to be advancedthrough the passage 32 thereby reducing the size of the loop 40 andcausing the band 11 to flex about its connection to the head 14 at 17and firmly grip around the article or articles 39. The axial reactiveforce along the screw shank 28 created through cooperation between thethreads 29 on the shank 28 and teeth 20 is resisted by the end wall 26of the chamber 22 thereby enabling the band 11 to be advanced and theloop 40 to be reduced in size. Further the force applied by the screw 23is essentially applied to linear sections 34 of the band 11 adjacent thehead 14 and not to curved sections of the band 11 reducing the tendencyfor slipping between the thread 29 and teeth 20. Thus the thread 29 onthe shank 28 of the screw 23 is engaged fully with a number of teeth 20of the band 11 This facilitates tightening of the band 11 and alsoapplication of a sufficient clamping force. Further the configuration ofthe clamp 10 ensures that the article or articles 39 are clampedsubstantially around the full circumference of the band 11 because theband 11 itself is contact in the almost the entire periphery of thearticles 39 with the head 14 extending generally tangentially from thearticles 32 and the formed band loop 40. Even gripping around the fullcircumference of the articles 39 is further facilitated by the taperedfinger 37 which fills the space between the band section 41 and articles39 adjacent the head 14.

FIG. 6 illustrates the manner in which the clamp 10 of the invention maybe used to grip articles 42 of smaller diameter. It will be appreciatedthat the same clamp 10 as used in FIG. 5 may also be used for thearticles 42. Thus as the screw 23 is rotated to tighten the band 11about the articles 42, the band 11 will simply bend or flex furtherabout its connection 17 to the head 14 such that the full circumferenceof the articles 42 can be gripped. The tapered finger 37 will alsodeflect to a greater extent to fill the space between the band section41 and articles 42 adjacent the head 14. In both of the examplesillustrated in FIGS. 5 and 6, gripping around substantially the fullperiphery of the articles 39 and 42 is particularly important where theclamp 10 is to be used for pressure applications for example clampingpressure hoses.

In an alternative method of use, the band 11 may be initially loopedabout the articles to be gripped with the distal end 13 passed throughthe passage 32 of the head 14 and tightened by hand to reduce the sizeof the loop 40 by pulling the band 11 relative to the head 14. The screw23 may then be inserted into the open end 25 of the chamber 22 of thehead 14 and rotated until it seats fully within the chamber 22 withfurther rotation of the screw 23 through cooperation between the thread29 on the screw shank 28 and teeth 20 of the band 11 causing tighteningof the band 11 about the article.

The band 11 in this embodiment may have a width of 8 mm and may be ofvarying lengths to suit the application such as 100, 200 and 300 mm.Alternatively, the band 11 may be simply cut to length. Further in thisembodiment the threads on the worm screw 23 have a pitch of 2.5 mm tomatch a similar pitch of the teeth 20 on the band 11. It will beappreciated however that the clamp 10 may be made in different sizes.

In the embodiment described an illustrated, the clamp 10 is primarilysuitable for tightening around an article or articles to effect clampingthereof. Rotation of screw 23 in the opposite direction to effect anincrease in size of the loop 40 can only be achieved if the screw 23 isrestrained against withdrawal from the chamber 22 by for example anaxial force applied to the screw 23. This construction however enablesthe clamp 10 to be of a simplified construction permitting the screw 23to be simply inserted into the chamber 22 of the head 14 after the band11 is looped around the article or articles. If the clamp 10 is to bereleased from the article or articles, the band 11 may be simply severedby a suitable cutting tool or the screw 23 rotated counter clockwiseuntil it is moved out of the chamber 22. In an alternativeconfiguration, however, the screw 23 can be made captive within thechamber 22.

It will be appreciated that the teeth 20 on the band 11 may be variousdifferent designs to suit the configuration of the thread on the wormscrew 23 and may in the case a metal band be grooves or slots.

The section 19 of the band 11 is shown in the embodiment to join theremainder of the band 11 at a transverse join line, however the section19 may curve smoothly into the remainder of the band 11. The sections 19may be of various curvatures or in some embodiments may be linear anddeflected in use to lie against the article being gripped.

The body 21 of the head 14 whilst shown to be of stepped configurationmay be of constant cross section through its length. Further whilst theembodiment shows a cut out region 43 between the lower portion 27 of thebody 21 and wall 33, it is not necessary to have the cut out region 43as the flanges 34 may be extended for the full length of the body 21 andwall 33.

Typically the clamp 10 is moulded of Nylon or any other suitableplastics material which provides sufficient flexibility in the band andrigidity of the head 14. The clamp 10 may be manufactured with the screw23 formed integrally with the head 14 and associated band 11 andconnected thereto by a frangible portion which allows it to be easilydetached. Preferably all of the components of the clamp 10 aremanufactured by injection moulding with a single die cavity forming allcomponents. In some embodiments however, the band 11 and associated head14 may be formed in one mould cavity and the screw 23 in a separate diecavity. In yet an alternative arrangement, the screw 23 may be formed ofmetal. Whilst the clamp of the embodiment has been designed to bemanufactured in plastics however, it will be appreciated that the clampmay also manufactured in metal.

All other variations and modifications to the invention as would beapparent to persons skilled in the art are deemed to fall within thebroad scope and ambit of the invention as herein defined in the appendedclaims.

1. An article clamp comprising: an elongated flexible band, said bandhaving on one side a plurality of spaced teeth, said band having aproximal end and a distal end, a head having a chamber for receivingscrew means for cooperation with said teeth on said band, said chamberhaving a longitudinal axis and said head having a proximal end and adistal end, the proximal end of said band being connected to saidproximal end only of said head and extending away therefrom at an acuteangle to said head relative to said longitudinal axis of said chambersuch that said distal end of said head is spaced from and free of saidband, said head further having a passage extending longitudinallytherethrough from said proximal end to said distal end for receivingsaid distal end of said band to form said band into a loop, and saidscrew means being adapted in use to cooperate with said teeth on saidband such that when said screw means is rotated in a first direction,said loop is decreased in size to clamp around a said article.
 2. Aclamp as claimed in claim 1 wherein said band has a main body carryingsaid teeth, said main body having a substantially constant cross sectionalong its length up to its connection to said head.
 3. A clamp asclaimed in claim 1 or claim 2 wherein said band includes a sectionextending from the proximal end of the head which is of an arcuateconfiguration longitudinally of said band, said band section being freeof said teeth.
 4. A clamp as claimed in claim 1 wherein said teethcomprise a plurality of raised lugs formed integrally with and extendingtransversely of the band.
 4. A clamp as claimed in claim 3 wherein saidteeth terminate short of opposite side edges of said band.
 5. A clamp asclaimed in claim 1 wherein said chamber is substantially circular incross section so as to closely accommodate the screw means butpermitting rotation thereof about said longitudinal axis.
 6. A clamp asclaimed in claim 5 wherein said chamber is open at the distal end of thehead to allow insertion of the screw means therein and is closed by awall at its proximal end for cooperation with an inner end of the screwmeans.
 7. A clamp as claimed in claim 1 wherein said screw means is inthe form of a worm screw provided with a shank having a thread thereonfor cooperation with the teeth of the band.
 8. A clamp as claimed inclaim 7 wherein said worm screw includes a head provided with screw slotfor engagement by a screwdriver for rotation of said worm screw.
 9. Aclamp as claimed in claim 7 wherein said worm screw includes a head,said head being shaped so as to be adapted for cooperation with aspanner or socket tool.
 10. A clamp as claimed in claim 1 wherein saidhead includes a main body in which said chamber is located.
 11. A clampas claimed in claim 10 wherein said passage is of re-entrant form incross section such that the band can be captured therein.
 12. A clamp asclaimed in claim 11 wherein said passage is intersected along its lengthby said chamber to define an entrance into said chamber through whichsaid teeth of said band project for engagement by said screw means. 13.A clamp as claimed in claim 10 wherein said head includes a planar wallspaced from said main body and wherein said passage is defined betweensaid planar wall and said main body.
 14. A clamp as claimed in claim 13wherein said connection between said band and said head is made betweensaid wall at the proximal end of said head and said band, said bandextending at an acute angle away from said wall and in the direction ofsaid head.
 15. A clamp as in claimed in claim 14 wherein lateralextensions are provided on opposite sides of said band to provideadditional support to said band at its connection to said wall.
 16. Aclamp as claimed in claim 13 wherein a flexible finger aligned with saidwall extends beyond the connection of said band to said wall, saidflexible finger being sandwiched in use between said band and article.17. A moulded plastics article clamp comprising: an elongated flexibleband, said band having a proximal end and a distal end, a head formedintegrally with said band and having a chamber therein, said chamberhaving a longitudinal axis and said head having a proximal end and adistal end, the proximal end of said band being connected to saidproximal end of said head and said band extending away from said head atan acute angle to said head relative to said longitudinal axis such thatsaid distal end of said head is spaced from and free of said band, saidhead further having a passage therethrough extending from said proximalend to said distal end for receiving said distal end of said band toform said band into a loop, and a worm screw in said chamber forcooperating with said band whereby rotation of said screw in a firstdirection about said longitudinal axis causes said loop to be decreasedin size to clamp around a said article.
 18. A clamp as claimed in claim117 wherein said band has a main body carrying said teeth and whereinsaid main body has a substantially constant cross section up to itsconnection with said head.